Method and system for continuously producing hydrogen, heat and aluminum oxides on-demand

ABSTRACT

A method and system for producing hydrogen gas, heat and an oxide component using water splitting process is disclosed. The system comprises a dry first chamber containing a passivating-oxide preventing agent that receives a solid material feedstock and dissolves the solid material feedstock in the passivating-oxide preventing agent. The passivating-oxide preventing agent becomes saturated with the solid material in the first chamber and is then transferred to a second chamber without contact with water. In the second chamber, the solid material saturated in the passivating-oxide preventing agent reacts with the water so as to generate hydrogen gas, an oxide component and heat. Following the reaction, the solid material depleted passivating-oxide preventing agent and water is recycled to be re-used in the water splitting process.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application relates to the co-owned U.S. patent applicationSer. No. 14/261,791 filed on Apr. 25, 2014 which claimed priority fromboth U.S. provisional application Ser. No. 61/819,787, filed on May 6,2013 and U.S. provisional application Ser. No. 61/815,856, filed on Apr.25, 2013. The present application also relates to the co-owned U.S.patent application Ser. No. 14/279,758, filed on May 16, 2014, whichclaimed priority from U.S. provisional application Ser. No. 61/823,997,filed on May 16, 2013. The disclosures of these prior provisional andutility applications are incorporated herein as if set out in full.

BACKGROUND OF THE DISCLOSURE

Technical Field of the Disclosure

The present embodiment relates in general to a method and apparatus forgenerating hydrogen. More specifically, the present disclosure relatesto a method and system for continuously producing hydrogen gas, heat andaluminum oxide on-demand from solid aluminum using a water splittingprocess.

Description of the Related Art

Hydrogen can be generated by a variety of methods, including natural gasreforming, electrolysis, thermochemical reaction and photo catalyticmethodologies. These methodologies produce carbon dioxide as aby-product, which requires a large amount of electrical energy which isexpensive and has a large, negative environmental impact. These methodsrequire solar energy with temperatures exceeding 1000 degrees Celsius,highly corrosive reactants and/or products and expensive reagents,complex nanostructured solids, and/or sacrificial oxidants or reductantsother than water.

A number of variants of water split reaction used to produce hydrogenhave been devised to overcome these problems. The water split reactioncontemplates a fuel for splitting water into hydrogen and an oxide. Inthese reactions aluminum is used to generate hydrogen from water.Commonly, aluminum oxide compounds can be produced from bauxite ores byBayer's process. In the water splitting process, the hydrogen isreleased as a gas and the oxygen combines with the aluminum to form thealuminum oxide compounds. The aluminum oxide compounds are produced as aprotective oxide layer on the aluminum in contact with water at ambienttemperature.

Aluminum has a tendency to be self-protecting by forming the aluminumoxide that inhibits reactions required for the formation of hydrogen andthus in some cases it is difficult, if not impossible, to use on a longterm basis. Therefore, it has been accepted by those skilled in the artthat the use of aluminum in a reaction with water to generate hydrogengas requires that the protective oxide layer is efficiently andcontinuously removed, and that the reaction is kept at an elevatedtemperature.

In one prior art reference, U.S. Pat. No. 4,358,291, the inventorsdisclosed that if aluminum (Al) is dissolved in a liquid solution ofgallium (Ga) or a liquid mixture of Ga and indium (In) at or near roomtemperature, then brought into contact with water, the Al in the liquidsolution at the water interface would split water molecules (H₂O) intohydrogen gas, alumina (Al₂O₃), and generate heat. This reaction willproceed until all elemental Al in the liquid solution is converted toalumina. The solid aluminum (Al) will dissolve in dry, air exposedliquid melts of gallium (Ga), Ga-indium (Ga—In), or Ga—In-tin (Ga—In—Sn)at or near room temperature up to the solubility limit of about 2-3weight percent Al.

When inert solid Al is dissolved in liquid Ga melt the solute aluminumis no longer passivated with alumina, its native oxide. Hence, whenwater is in contact with aluminum saturated gallium melt, the aluminumatoms at an interface between the melt and water are free to split thewater into hydrogen gas and alumina while generating heat. The galliumused is inert with respect to splitting water, and hence reusable.

One drawback of this approach is that if the Al that is dissolved in theliquid solution in a dry environment and reacted to completion in thepresence of excess water, the liquid solution is now under-saturatedwith respect to Al. This means that the liquid could theoretically besaturated with additional Al. When a solid piece of Al (whose density isless than liquid Ga) is floated on top of an under-saturated liquid ofGa in the presence of excess water, the solid piece of Al will notdissolve into an under-saturated Ga, Ga—In, or Ga—In-tin (Sn) liquid ator near room temperature. Further, the solid Al does not dissolve inunder-saturated liquid Ga in the presence of water due to the fact thatthere is a layer of water between the liquid Ga and the solid Al thatforms a barrier layer of alumina that is thicker than the alumina layerthat forms between Ga and Al in air. Attempts have been made to findother methods to cope with these problems. One method is to heat amixture of solid Al and Ga (or Ga—In or Ga—In—Sn) in an inert containerabove the melting point of Al, and then return the melt mixture back toroom temperature. However, this method requires the use of cruciblematerials that will not react with Al melts and causes difficulty toempirically find optimal cooling rates and composition that will renderthe mixture suitable for practical applications.

Another drawback of this approach is that if the liquid solutioncontaining Al is cooled to the point of freezing into a solid solution,very little reaction will occur. This is because unlike the case forliquid solutions, where the Al atoms can continuously diffuse towater-solution interface and react until the Al has all reacted, Alatoms in the frozen solution cannot move to the interface. Hence, onlythose Al atoms at the frozen solution surface can react with water. Oncethe Al atoms at the frozen solution surface react with water, thereaction stops.

In light of the foregoing, there is a need for a method and system forcontinuously producing hydrogen gas, heat, and aluminum oxides on-demandfrom solid aluminum using water splitting techniques that avoid theinherent problems with current technologies. Such a method and systemwould need to be implemented on an inexpensive and economically viablebasis. Such a method and system would provide an under-saturated galliumliquid melt that will not react with water when covered with water orexposed to air. Further, such a method and apparatus would continuouslydissolve a solid-state Al or other liquid metals into theunder-saturated Ga liquid melt and its alloys in the presence of waterto enable the continuous generation of hydrogen gas; the continuousproduction of economically important oxides of Al or other liquidmetals; and the continuous generation of heat. Such a method and systemwould not be passivated with alumina by continuously dissolving Al intoliquid Ga in the present of excess water. Such a method and system wouldinclude a plurality of chambers in which the solid-state Al iscontinuously dissolved in the Ga liquid melt and Al saturated Ga melt isreacted with the water at water-liquid melt interface separately tosplit the water into hydrogen gas and aluminum oxide. Furthermore, sucha method and system would include at least one means for separatingwater and gallium from the water-oxide mixture for the purpose ofreusing the water and gallium during the process. Such a method andsystem would include at least one means for collecting the aluminumhydroxide and converting it into ultra-high purity (UHP) alumina.Finally, such a method and system would provide a continuous andeconomical conversion of the solid-state Al of any purity to on-demandUHP hydrogen and UHP alumina, using any kind of water. The presentembodiment accomplishes these objectives.

SUMMARY OF THE DISCLOSURE

To minimize the limitations found in the prior art, and to minimizeother limitations that will be apparent upon the reading of thespecification, the preferred embodiment of the present inventiondiscloses a method and system for producing hydrogen gas, heat and anoxide component from a solid material feedstock using water splittingtechniques. Water splitting is achieved through an inventive system andmethod which dissolves a solid material feedstock, such as solidaluminum, into a liquid passivating-oxide preventing agent on a dry sideof the invention. For purposes of the invention, the dry side is devoidof any oxygen supplying reagent, such as water, or hydrogen peroxide.The passivating-oxide preventing agent becomes saturated with the solidmaterial feedstock on the dry side. An opposite side of the inventioncomprises a wet side which receives the saturated passivating-oxidepreventing agent from the dry side through fluid communication, whereinan oxygen supplying reagent, such as water is introduced to the wetside. The introduction of water to the wet side causes a water splittingreaction with the solid material feedstock dissolved in thepassivating-oxide preventing agent to produce hydrogen gas, heat and anoxide component. As the solid material is depleted on the wet side, aconcentration gradient is dynamically produced between the depleting wetside and the solid material saturated dry side. This gradient betweenthe dry and wet sides causes the solid material feedstock dissolved inthe passivating-oxide preventing agent to diffuse from the dry side tothe wet side. If the diffusion flow rate of the solid material from thedry side to the wet side is insufficient to sustain an appropriatereaction rate target, the forces of convection can be added viamechanical stirring, for example, to aid the water splitting reactionrate.

More specifically, the system comprises a first chamber filled with apassivating-oxide preventing agent that receives a solid materialfeedstock. The passivating-oxide preventing agent is substantially inertto water in an effective amount to prevent passivation of a solidmaterial feedstock during oxidation. The solid material feedstock iscapable of dissolving in the passivating-oxide preventing agent andsolid material saturated passivating-oxide preventing agent istransferred to a second chamber. In the second chamber the solidmaterial saturated in the passivating-oxide preventing agent reacts withthe water so as to generate the hydrogen gas, oxide component and heat.The passivating-oxide preventing agent is recycled back to the secondchamber and then to the first chamber. Similarly, the water is recycledback to the second chamber and used in the water splitting process. In apreferred embodiment, the solid material feedstock is aluminum feedstockand the oxide component is aluminum hydroxide. The passivating-oxidepreventing agent is an under-saturated molten gallium.

In one embodiment, the liquid melt used in the hydrogen generationprocess is enhanced by the addition of a liquid-phase gallium-indiumalloy that consists essentially of about 80% (eighty percent) galliumand 20% (twenty percent) indium (80/20 (Ga/In). In another embodiment,the liquid melt used in the hydrogen generation process is enhanced bythe addition of a liquid-phase gallium-indium-tin alloy that consistsessentially of 68% (sixty-eight percent) Ga-22% (twenty-two percent)In-10% (ten percent) Sn.

The solid material feedstock is selected from the group consisting of: astrip of aluminum, a rod of aluminum, a pellet of aluminum, a tube ofaluminum, granules of aluminum and a powder of aluminum and may besubstantially pure aluminum or may contain other materials in the way ofimpurities or alloys so long as they do not impede the oxidation processand action of the passivating-oxide preventing agent.

A method for producing hydrogen gas and an oxide component using watersplitting process is contemplated in one aspect of the invention. Afirst chamber is filled with a liquid melt and a solid materialfeedstock is inserted into the liquid melt. The solid material feedstockis submerged into the liquid melt so that the solid material feedstockdynamically dissolves in the liquid melt saturating the liquid melt. Asolid material saturated liquid melt is passed to a second chamber via afirst connection tube. Water is introduced to the second chambercontaining the solid material saturated liquid melt via a water inlet.The solid material saturated in the liquid melt is reacted with thewater at a water-liquid melt interface so as to split the water into thehydrogen gas, the oxide component and heat until the solid materialtherein is depleted. Then, water-oxide mixture is passed to a centrifugeor other filtering mechanism via an outlet tube to separate the oxidecomponent, water and molten gallium. The outlet tube is externallymounted with a heat exchanger pipe which removes excess heat generatedduring the process. The oxide component is passed to a furnace whereinthe oxide component is dehydrated and heated to generate an ultra highpurity (UHP) alumina. The process is continued until the solid materialfeedstock submerged is converted into the ultra high purity (UHP)alumina. Thus, the method provides continuous dissolution of the solidmaterial feedstock into the passivating-oxide preventing agent and itsalloys in the presence of excess water to enable continuous generationof the hydrogen gas, oxide component and heat.

The solid material feedstock is immersed in the Ga melt at ambienttemperature or temperature between 30° C. and 95° C. in the firstchamber. The solid material saturated Ga melt is transferred to thesecond chamber in which the water is introduced above the surface of theAl saturate Ga melt to split the water into aluminum hydroxide, hydrogengas and heat. The process will continue until the solid-state materialsare continuously immersed into the Ga and are converted to aluminumhydroxide. The ammonium hydroxide is dehydrated and heated to generatehigh purity alumina. The Ga melt is recycled back to the second chamberand then to the first chamber. Similarly, the water is recycled back tothe second chamber and used in the water splitting process.

These and other advantages and features of the present invention aredescribed with specificity so as to make the present inventionunderstandable to one of ordinary skill in the art.

BRIEF DESCRIPTION OF THE DRAWINGS

Elements in the figures have not necessarily been drawn to scale inorder to enhance their clarity and improve understanding of thesevarious elements and embodiments of the invention. Furthermore, elementsthat are known to be common and well understood to those in the industryare not depicted in order to provide a clear view of the variousembodiments of the invention, thus the drawings are generalized in formin the interest of clarity and conciseness.

FIG. 1 illustrates a flow chart showing a closed cycle using a solidmaterial feedstock, an oxygen supplying reagent and a passivating-oxidepreventing agent to produce hydrogen gas, heat and an oxide componentusing a water splitting process in accordance with the preferredembodiment of the present invention; and

FIG. 2 illustrates an exemplary embodiment of a system for producing thehydrogen gas and an ultra high purity (UHP) alumina using the watersplitting process.

FIG. 3 illustrates a cross-sectional view of a reaction vessel inaccordance with an alternative embodiment of the invention.

FIG. 4 illustrates an elevated perspective view of the reaction vesselshown in FIG. 3.

DETAILED DESCRIPTION OF THE DRAWINGS

In the following discussion that addresses a number of embodiments andapplications of the present invention, reference is made to theaccompanying drawings that form a part hereof, and in which is shown byway of illustration specific embodiments in which the invention may bepracticed. It is to be understood that other embodiments may be utilizedand changes may be made without departing from the scope of the presentinvention.

For the purposes of promoting an understanding of the principles of theinvention, reference will now be made to the embodiments illustrated inthe drawings and described in the following written specification. It isunderstood that any alterations and modifications to the illustratedembodiments as would normally occur to one skilled in the art to whichthis invention pertains are encompassed with the scope of the invention.

In a preferred embodiment of the present invention, a system is providedin which aluminum is reacted with water and/or hydrogen peroxide toproduce hydrogen and heat. If hydrogen peroxide is used, oxygen isgenerated in addition to hydrogen. The aluminum is treated with apassivation preventing agent so that the aluminum reacts continuouslywith the water to split the water into hydrogen and aluminum oxide. Thehydrogen may be provided to a power generation element, such as a fuelcell or a combustion engine in a vehicle. More broadly, thealuminum-to-hydrogen methods of the present invention may be combinedwith apparatuses that convert the hydrogen, oxygen and heat intoelectrical, mechanical or thermal power.

The solid material feedstock is a metallic aluminum feedstock thatoxidizes at low or near room temperature, but as noted above the solidmaterial 11:1 feedstock forms a passivating oxide layer which inhibitsfurther oxidation. In the present invention, molten gallium serves asthe passivating-oxide preventing agent that inhibits the passivationnature of the aluminum oxide layer and a plurality of chambers toprovide submerging of solid material feedstock in the molten gallium,splitting of water and recycling of the molten gallium separately tocontinuously and economically convert solid aluminum feedstock of anypurity to on-demand ultra high purity (UHP) hydrogen and UHP alumina,using any kind of water. According to one embodiment of the presentinvention, the Al—Ga to hydrogen conversion process is enhanced by theaddition of a liquid-phase gallium-indium alloy. According to anotherembodiment of the present invention, the Al—Ga to hydrogen conversionprocess is enhanced by the addition of a liquid-phase gallium-indium-tinalloy. Gallium, gallium-indium, gallium-indium-tin and other suitablealloys are desirable because they become liquid at low temperatures andhave low vapor pressures, thereby allowing a wide temperature window forthe aluminum oxidation reaction.

The process for controlled oxidation of the aluminum using water as theoxygen supplying reagent and gallium as the passivating oxide inhibitor,follows these reaction equations:2Al+3H₂O→+Al₂O₃+3H₂+ΔE₁  1)2H₂+O₂→2H₂O+ΔE₂  2)

where

ΔE1=407 kJ/mole Al=15.1 kJ/g of aluminum, and

ΔE2=286 kJ/mole H₂=429 kJ/mole Al=15.9 kJ/g of aluminum.

This process is renewable because the Al₂O₃ produced can be convertedback into aluminum using reactions such as the following:2Al₂O₃+ΔE₃→4Al+3O₂  3)2Al₂O₃+3C+ΔE₄→4Al+3CO₂  4)

where

ΔE3=877 kJ/mole of Al=32.5 kJ/g of aluminum, and

ΔE4=582 kJ/mole of Al=21.6 kJ/g of aluminum.

The energy density of aluminum as a fuel compares extremely favorably toother known technologies, as demonstrated by the following Table I:

TABLE I Energy Density Efficiency Net Power Emission Fuel (kJ/g) Engine(%) (kJ/g) Products Aluminum 31 Stirling or 25-50 7.8-15.5 Al₂O₃ FuelCell 25 7.8 H₂O Gasoline 47.5 Internal 20-25 9.5-11.9 CO₂, CO,Combustion NO_(x), SO_(x) etc. Methanol 23 Reformer + 30-40 6.9-9.2 H₂O,CO₂, Fuel Cell CO

It can first be noted that the emission products from the aluminumsource are fully recyclable. The water may be recycled to provideadditional oxidizer for the aluminum in the reaction process. Thealuminum oxide is environmentally benign and readily recyclable intoaluminum that can be reused to generate hydrogen. It can also be notedthat in the Stirling engine the heat product of the reaction is alsoused in power generation. Even if only the hydrogen is used (as in thefuel cell), the resulting efficiency is still 25 percent.

Since gallium is inert, substantially all of the gallium contained inthe aluminum-gallium mixture remains after the aluminum has beenconsumed. The gallium may be re-used and is hence nearly 100%recyclable.

As an aside, the overall efficiency of the aluminum source protocolshould also consider the efficiency of recycling the Al₂O₃ back intousable aluminum. Applying Equations 3 and 4 above, the cycle efficiencyranges from 12-18 percent, where cycle efficiency is the energygenerated by the oxidation of the aluminum divided by the energyrequired to recycle the aluminum. This cycle efficiency assumes thatonly 25% of the available energy of the oxidation process is captured asuseful power. Obviously, if more energy is captured (such as the heatgenerated by the reactions in Equations 1 and 2) then the recycleefficiency will improve.

The process steps used in the present invention are illustrated in theflow chart of FIG. 1. A source of solid material feedstock 10 isdissolved in a passivating-oxide preventing agent 11 which prevents theformation of an oxide component 22 on the surface of the solid materialfeedstock 10 when exposed to moisture or water. The submerged solidmaterial feedstock 10 is saturated with the passivating-oxide preventingagent 11 to produce solid material saturated passivating-oxidepreventing agent in a first chamber 12. The solid material feedstock 10is submerged in the passivating-oxide preventing agent 11 in such a waythat the solid material feedstock 10 does not make direct contact withmoisture/water. The solid material saturated passivating-oxidepreventing agent is passed to a second chamber 13 which either containsoxygen supplying reagent 14 or the oxygen supplying reagent 14 issupplied to the second chamber 13. The solid material saturated in thepassivating-oxide preventing agent is reacted with the oxygen supplyingreagent 14 like water and/or hydrogen peroxide and oxidized with theoxygen supplying reagent 14 in the second chamber 13. During theprocess, the solid material feedstock 10 is submerged in the liquidpassivating-oxide preventing agent 11 and dissolves until the solubilitylimit of the passivating-oxide preventing agent is reached. The solidmaterial feedstock 10 is a metallic aluminum feedstock. The metallicaluminum feedstock may be, for example, selected from the groupconsisting of: a strip of aluminum, a rod of aluminum, a pellet ofaluminum, a tube of aluminum and granules of aluminum and may besubstantially pure aluminum or may contain other materials in the way ofimpurities or alloys so long as they do not impede the oxidation processand action of the passivating-oxide preventing agent 11. The aluminumordinarily forms an oxide coating upon exposure to the atmosphere,completely passivating the surface and inhibiting further oxidation.However, at a temperature sufficient to keep the passivating-oxidepreventing agent 11 in a liquid state, the passivating-oxide preventingagent 11 dynamically dissolves the solid material feedstock 10 therebybreaking up and preventing the formation of the oxide layer. Thisdisruption of the oxide formation/depositation allows the oxidationreaction in the second chamber 13 to continue and consume more of thesolid material feedstock 10. The solid material feedstock 10 saturatedin the passivating-oxide preventing agent 11 is reacted with the oxygensupplying reagent 14 to split the oxygen supplying reagent 14 intohydrogen gas 15, the oxide component 22 and heat 17 until the solidmaterial feedstock 10 is depleted. Thus, the process will continue untilthe solid material feedstock 10 saturated in the passivating-oxidepreventing agent is continuously reacted with oxygen supplying reagent14 and is converted to the hydrogen gas 15, oxide component 22 and heat17. The oxygen supplying reagent 14 is introduced to the second chamber13 via an external source.

The heat 17 and hydrogen gas 15 are co-generated energy outputs and theheat 17 released during the process is removed utilizing a heatexchanger pipe 18. Water-oxide mixture 16 has undergone centrifugation19 in the preferred embodiment shown to recover the passivating-oxidepreventing agent 20 obtained from the passivating-oxide preventing agent11 that is not otherwise consumed during the reaction. The recoveredpassivating-oxide preventing agent 20 is returned back to the secondchamber 13 and then to the first chamber 12. During centrifugation 19,the oxide component 22 is separated from water 21 and the water 21 iscaptured and returned to the second chamber 13 where it is used in thewater splitting process. Alternatively to centrifugation 19, acontinuous filtration process (not shown) could provide separation ofwater 21 from the oxide component 22. The oxide component 22 producedhas undergone dehydration/heating 23 to generate an ultra high purity(UHP) alumina 24.

Prevention of the passivation oxide layer is accomplished by submergingthe solid material feedstock 10 below a surface of the passivating-oxidepreventing agent 11. Submerging involves the passivating-oxidepreventing agent 11 spreading on the surface and adheres to the solidmaterial feedstock 10. The solid material feedstock 10 is dissolved inthe passivating-oxide preventing agent 11 and thereby thepassivating-oxide preventing agent 11 becomes saturated with the solidmaterial feedstock 10. The dissolved solid material feedstock 10 isreacted with the oxygen supplying reagent 14 so as to generate thehydrogen gas 15, oxide component 22 and heat 17. The passivating-oxidepreventing agent 11 is an inert gallium melt or gallium-indiumliquid-phase alloy or gallium-indium-tin liquid-phase alloy.

In a preferred embodiment, a system for producing hydrogen gas and anoxide component using water splitting process is illustrated. The systemincludes a plurality of chambers in fluid communication, the pluralityof chambers that includes a first chamber filled with a liquid meltreceives a solid material feedstock and a second chamber receives asolid material saturated liquid melt from the first chamber. The solidmaterial saturated in the liquid melt is reacted with the water at awater-liquid melt interface so as to split the water into the hydrogengas, the oxide component and heat until the solid material therein isdepleted. The oxide component is dehydrated and heated to generate anultra high purity (UHP) alumina.

In one aspect of the present invention, a method for producing hydrogengas and an oxide component using water splitting process is disclosed. Afirst chamber is filled with a liquid melt and a solid materialfeedstock is inserted into the liquid melt. The solid material feedstockis submerged into the liquid melt so that the solid material feedstockdynamically dissolves in the liquid melt. A solid material saturatedliquid melt is passed to a second chamber via fluid communication. Inthe preferred embodiment, the fluid communication is accomplished by afirst connection tube. Water is introduced to the second chambercontaining the solid material saturated liquid melt via a water inlet.The solid material saturated in the liquid melt is reacted with thewater at a water-liquid melt interface so as to split the water into thehydrogen gas, the oxide component and heat until the solid materialtherein is depleted. Then, water-oxide mixture is passed to a centrifugevia an outlet tube to separate the oxide component, water and moltengallium. The outlet tube is externally mounted with a heat exchangerpipe which removes excess heat generated during the process. The oxidecomponent is passed to a furnace wherein the oxide component isdehydrated and heated to generate an ultra high purity (UHP) alumina.The process is continued until the solid material feedstock submerged isconverted into the ultra high purity (UHP) alumina. The solid materialfeedstock is aluminum feedstock, the oxide component is aluminumhydroxide and the liquid melt is an under-saturated molten liquidgallium melt which consists essentially of about 100% (hundred percent)by weight molten gallium.

According to one embodiment of the present invention, the liquid meltused in the hydrogen generation process is enhanced by the addition of aliquid-phase gallium-indium alloy that consist essentially of about 80%(eighty percent) gallium and 20% (twenty percent) indium (80/20(Ga/In)). According to another embodiment of the present invention, theliquid melt used is a liquid-phase gallium-indium-tin alloy that consistessentially of 68% (sixty-eight percent)-22% (twenty-two percent)-10%(ten percent).

In one specific example illustrated in FIG. 2, a system 30 for producinghydrogen gas, heat and an oxide component using water splitting processis illustrated. The system 30 includes a plurality of chambers which arein fluid communication with a flowline. A liquid melt 31 ofunder-saturated molten gallium is provided in a first chamber 32 at anambient temperature. The first chamber 32 is made of a heat-resistantand pressure-resistant material. In the water splitting process, thefirst chamber 32 is maintained at a temperature between 30° C. and 95°C. and a controlled pressure. The heat-resistant and pressure-resistantmaterial has an iron content of 70% or higher, or stainless steel,carbon steel, or a mixture thereof. Accordingly, when the first chamber32 is made of a material of iron and stainless steel, it will notinfluence reactions.

A solid material feedstock 33 is disposed inside the first chamber 32 insuch a way that the solid material feedstock 33 is continuouslydissolving in the molten gallium 31. Because the solid materialfeedstock 33 is less dense but heavier than the displaced molten gallium31 it will sink to a bottom wall of the first chamber 32. Thus, thesolid material feedstock 33 is submerged below the surface of the moltengallium 31 without the need of applying an external force. The solidmaterial feedstock 33 dynamically dissolves in the molten gallium toproduce a solid material saturated molten gallium. Preferably, the solidmaterial feedstock 33 is aluminum feedstock and the oxide component isaluminum hydroxide or alumina.

The aluminum saturated molten gallium is fed into a second chamber 34,which preferably is a reactor. The second chamber 34 either containswater or water is introduced into the second chamber 34 from an externalwater source 36 via a water inlet 35 that is positioned at a first inletof the second chamber 34. The water inlet is in fluid communication witha water pump 37 that is adapted to pump water to the second chamber 34from the external water source 36. The flow amount of the water pump 37and pressure released during the flow of water is controlled byadjusting a pressure reduction valve 38. The solid material saturatedmolten gallium is fed into a second chamber 34 via a first connectiontube 39 that is positioned at a second inlet of the second chamber 34.The first connection tube 39 is positioned below the water-liquid meltinterface so as to prevent any incursion of water from the secondchamber to the first chamber, while maintaining free flow of the moltengallium from the first chamber to the second chamber. When watercontacts the aluminum saturated molten gallium, aluminum atoms at awater-liquid melt interface 67 it reacts with the water so as to splitthe water into the hydrogen gas 40, the oxide component and heat untilthe aluminum therein is depleted. The pressure reduction valve 38positioned on the outlet of the second chamber 34 reduces the pressurefor the hydrogen gas 40 when released from the second chamber 34. Whenthe gallium-aluminum melt 41 in the second chamber 34 becomes partiallyor totally depleted of aluminum, then the gallium-aluminum melt 41 isdynamically returned to the first chamber 32 via a second connectiontube 42 that is positioned at an outlet of the second chamber 34. Thus,the aluminum from the feedstock 33 in the first chamber 32 is dissolvedin the depleted gallium melt 31 and restores it to an aluminum-saturatedcondition. Preferably, the first connection tube 39 and the secondconnection tube 42 provides controlled flow of the aluminum-saturatedmolten gallium from the first chamber 32 to the second chamber 34 andrecovered gallium melt from the second chamber 34 to the first chamber32 respectively utilizing a two-way control valve 43 placed in the firstconnection tube 39. For instance, when the solid material saturatedmolten gallium is no longer needed, the first connection tube 39 isclosed, causing pressure to increase during the process. The pressure isreduced by the pressure reduction valve 38 placed in the secondconnection tube 41.

During the continuous water splitting process in the second chamber 34the concentration of the oxide component dispersed in the water iscontinuously increased. Water-oxide mixture 44 is moved from the secondchamber 34 to at least one centrifuge 45 via an outlet tube 46. Thewater-oxide mixture 44 is centrifuged to separate the aluminumhydroxide, water and molten gallium. The outlet tube 46 is externallymounted with a heat exchanger pipe 47 which removes the heat generatedduring the process. During centrifugation, the molten gallium and wateris recovered and returned to the second chamber 34 from the at least onecentrifuge 45 via a recovery tube 48 that is positioned at a third inletof the second chamber 34. The recovered molten gallium and water ismixed with the other depleted gallium 41 in the second chamber 34. Then,the depleted molten gallium 41 is transported back to the first chamber32 containing molten gallium 31 continuously saturated with aluminum.

The wet aluminum hydroxide is passed to at least one furnace 49. Thealuminum hydroxide is dehydrated and heated to about 125° C. to convertthe aluminum hydroxide to an ultra high purity (UHP) alumina 50. Thewater from both the centrifuge 45 and dehydration furnace 49 is capturedand returned to the second chamber 34 where it is used in the watersplitting process. Thus, the solid material feedstock 33 dissolvescontinuously into the molten gallium 31 and its alloy in the presence ofexcess water at ambient temperature to enable the continuous generationof the hydrogen gas 40 and the continuous production of economicallyimportant oxides of the solid material feedstock 33. Thus, the systemand method provides a continuous and economic conversion of thesolid-state Al of any purity to on-demand UHP hydrogen 40 and UHPalumina 50, using any kind of water.

Referring to FIG. 3, an alternative embodiment for providing fluidcommunication of aluminum-saturated molten gallium between a dry sideand a wet side of the system is illustrated. A reaction vessel 60 isprovided comprised of a first inner chamber 62 and a second outerchamber 64. As further shown in FIG. 4, this reaction vessel 60 isconfigured as a cylinder where the first inner cylindrical chamber 62 issurrounded by the second outer cylindrical chamber 64. Thisconfiguration maintains a fluid communication between the first innerchamber 62 and second outer chamber 64 without necessitating theconnection tubes 39 and 42 of the prior embodiment. In this alternateembodiment reaction vessel 60, the first inner chamber 62 is bottomless66, while the second outer chamber has a bottom 68, thus allowingaluminum-saturated molten gallium or other passivating-oxide preventingagent 72 to fluidly communicate between the inner chamber 62 and outerchamber 64. The bottomless portion 66 of the inner chamber 62 resideswell beneath the interface 61 of the molten gallium or otherpassivating-oxide preventing reagent 72 and water 65 in the outerchamber 64, thus sealing the inner chamber 62 from incursion of water.As the solid aluminum feedstock 70 is dissolved in the molten gallium,it reaches an optimum saturation point that can be continuouslymaintained through submerging the solid aluminum feedstock at a rateconducive to continuous production. The inner chamber walls 74 create adry side 76 and a wet side 78 wherein the solid aluminum feedstock 70can be submerged in the molten gallium or other passivating-oxidepreventing agent 72 as herein described. The wet side 78 of the reactionvessel 60 is sealed completely from the dry side 76 and allows for thein-flow of water through a first inlet pipe 80, thus allowing the watersplitting process to proceed on the wet side 78 in the manner asdescribed in the prior embodiment. As the concentration of the oxidecomponent dispersed in the water is continuously increased on the wetside 78, it can be removed through an outlet pipe 82 and processed bycentrifugation or filtration to separate the water, aluminum hydroxideand molten gallium. The remainder of the system as previously describedwould be adapted to this reaction vessel 60 with the molten galliumbeing returned to the dry side 76 in the inner chamber 62, the waterbeing returned to the wet side 68 in the outer chamber 64 and thealuminum hydroxide being exposed to a furnace (not shown) to convert thealuminum hydroxide to an ultra high purity (UHP) alumina product.

While the invention has been illustrated and described in detail in thedrawings and foregoing description, the same should be considered asillustrative and not restrictive in character. It is not intended to beexhaustive or to limit the invention to the precise form disclosed. Manymodifications and variations are possible in light of the aboveteachings. It is intended that the scope of the present invention not belimited by this detailed description, but by the claims and theequivalents to the claims appended hereto.

What is claimed is:
 1. A method for producing hydrogen gas, heat and anoxide component using a water splitting process comprising: (a)providing a first chamber filled with a liquid melt, the liquid meltincludes an under-saturated molten gallium; (b) inserting a solidmaterial feedstock into the molten gallium wherein the solid materialfeedstock is submerged into the molten gallium so that the solidmaterial feedstock dissolves in the molten gallium; (c) passing a solidmaterial-saturated molten gallium to a second chamber via fluidcommunication; (d) introducing water via a water inlet to the secondchamber containing the solid material-saturated molten gallium; (e)reacting the solid material-saturated molten gallium with the water at awater-liquid melt interface so as to split the water into the hydrogengas, the oxide component and heat until the solid material therein isdepleted; (f) passing water-oxide mixture to a centrifuge via an outlettube externally mounted with a heat exchanger pipe wherein thewater-oxide mixture is centrifuged to separate the oxide component, thewater and the molten gallium while removing excess heat; (g) passing theoxide component to a furnace wherein the oxide component is dehydratedand heated to generate an ultra-high purity (UHP) alumina; and (h)repeating the steps (b) through (g) until the solid material feedstocksubmerged is converted into the ultra-high purity (UHP) alumina; whereinthe solid material feedstock is aluminum feedstock, the oxide componentis aluminum hydroxide and the molten gallium consists essentially ofabout 100% (hundred percent) by weight.
 2. The method of claim 1 whereinduring step (d) the water is introduced to the second chamber from anexternal water source via the water inlet.
 3. The method of claim 1wherein during step (e) the molten gallium in the second chamber isdynamically returned to the first chamber that contains the moltengallium via a second connection tube when the solid material feedstocksaturated in the molten gallium is partially or totally depleted of thesolid material.
 4. The method of claim 1 wherein insertion step (b)occurs at a temperature between 30° C. and 95° C.
 5. The method of claim1 wherein during step (f) the recovered molten gallium and water isdynamically returned to the second chamber via a recovery tube.
 6. Themethod of claim 1 wherein during step (g) the water is recovered anddynamically returned to the second chamber.
 7. The method of claim 1wherein the solid material feedstock is selected from the groupconsisting of: a strip of aluminum material, a rod of aluminum, a pelletof aluminum, a tube of aluminum, granules of aluminum and a powder ofaluminum.
 8. A method for producing hydrogen gas, heat and an oxidecomponent using a water splitting process comprising: (a) providing afirst chamber filled with a liquid melt, the liquid melt includes anunder-saturated gallium alloy; (b) inserting a solid material feedstockinto the gallium alloy wherein the solid material feedstock is submergedinto the gallium alloy so that the solid material dissolves in thegallium alloy; (c) passing a solid material saturated gallium alloy to asecond chamber via a first connection tube; (d) introducing water via awater inlet to the second chamber containing the solid materialsaturated gallium alloy; (e) reacting the solid material saturatedgallium alloy with the water at a water-liquid melt interface so as tosplit the water into the hydrogen gas, the oxide component and heatuntil the solid material therein is depleted; (f) passing water-oxidemixture to a centrifuge via an outlet tube externally mounted with aheat exchanger pipe wherein the water-oxide mixture is centrifuged toseparate the oxide component, the water and the gallium alloy whileremoving excess heat; (g) passing the oxide component to a furnacewherein the oxide component is dehydrated and heated to generate anultra-high purity (UHP) alumina; and (h) repeating the steps (b) through(g) until the solid material feedstock submerged is converted into theultra-high purity (UHP) alumina; wherein the solid material feedstock isaluminum, the oxide component is aluminum hydroxide and the galliumalloy consists essentially of about 80% (eighty percent) gallium and 20%(twenty percent) indium (80/20 Ga/In).
 9. The method of claim 8 whereinduring step (d) the water is introduced to the second chamber from anexternal water source via the water inlet.
 10. The method of claim 8wherein during step (e) the gallium alloy in the second chamber isdynamically returned to the first chamber via a second connection tubewhen the gallium alloy is partially or totally depleted of the solidmaterial feedstock.
 11. The method of claim 8 wherein insertion step (b)occurs at a temperature between 30° C. and 95° C.
 12. The method ofclaim 8 wherein during step (f) the recovered gallium alloy and water isdynamically returned to the second chamber via a recovery tube.
 13. Themethod of claim 8 wherein during step (g) the water is recovered anddynamically returned to the second chamber.
 14. The method of claim 8wherein the solid material feedstock is selected from the groupconsisting of: a strip of aluminum material, a rod of aluminum, a pelletof aluminum, a tube of aluminum, granules of aluminum and a powder ofaluminum.
 15. A method for producing hydrogen gas, heat and an oxidecomponent using a water splitting process comprising: (a) providing afirst chamber filled with a liquid melt, the liquid melt includes anunder-saturated gallium alloy; (b) inserting a solid material feedstockinto the gallium alloy wherein the solid material feedstock is submergedinto the gallium alloy so that the solid material dissolves in thegallium alloy; (c) passing a solid material saturated gallium alloy to asecond chamber via a first connection tube; (d) adding water via a waterinlet to the second chamber containing the solid material saturatedgallium alloy; (e) reacting the solid material saturated in the galliumalloy with the water at a water-liquid melt interface so as to split thewater into the hydrogen gas, the oxide component and heat until thesolid material therein is depleted; (f) passing water-oxide mixture to acentrifuge via an outlet tube externally mounted with a heat exchangerpipe wherein the water-oxide mixture is centrifuged to separate theoxide component, the water and the gallium alloy while removing excessheat; (g) passing the oxide component to a furnace wherein the oxidecomponent is dehydrated and heated to generate an ultra-high purity(UHP) alumina; and (h) repeating the steps (b) through (g) until thesolid material feedstock submerged is converted into the ultra-highpurity (UHP) alumina; wherein the solid material feedstock is aluminumfeedstock, the oxide component is aluminum hydroxide and the galliumalloy includes gallium, indium, and tin.
 16. The method of claim 15wherein during step (d) the water is introduced to the second chamberfrom an external water source via the water inlet.
 17. The method ofclaim 15 wherein during step (e) the gallium alloy in the second chamberis dynamically returned to the first chamber via a second connectiontube when the gallium alloy is partially or totally depleted of thesolid material feedstock.
 18. The method of claim 15 wherein insertionstep (b) occurs at a temperature between 30° C. and 95° C.
 19. Themethod of claim 15 wherein during step (f) the recovered gallium alloyand water is dynamically returned to the second chamber via a recoverytube.
 20. The method of claim 15 wherein during step (g) the water isrecovered and dynamically returned to the second chamber.
 21. The methodof claim 15 wherein the solid material feedstock is selected from thegroup consisting of: a strip of aluminum material, a rod of aluminum, apellet of aluminum, a tube of aluminum, granules of aluminum and apowder of aluminum.
 22. A method for producing hydrogen gas, heat and anoxide component using a water splitting process comprising: (a)providing a first chamber filled with a liquid melt, the liquid meltcomprising an under-saturated passivating-oxide preventing agent; (b)inserting a solid material feedstock into the passivating-oxidepreventing agent wherein the solid material feedstock is submerged intothe passivating-oxide preventing agent so that the solid materialfeedstock dissolves in the passivating-oxide preventing agent; (c)passing a solid material-saturated passivating-oxide preventing agent toa second chamber via fluid communication; (d) introducing water to thesecond chamber containing the solid material-saturated passivating-oxidepreventing agent; (e) reacting the solid material-saturatedpassivating-oxide preventing agent with the water at a water-liquid meltinterface so as to split the water into the hydrogen gas, the oxidecomponent and heat; (f) passing the water-oxide mixture to a centrifugevia an outlet tube externally mounted with a heat exchanger pipe whereinthe water-oxide mixture is centrifuged to separate the oxide component,the water and the molten gallium while removing excess heat; and (g)passing the oxide component to a furnace wherein the oxide component isdehydrated and heated to generate an ultra-high purity (UHP) alumina.